unfaithful

• 指不忠诚、不忠实的人，尤指对配偶或伴侣不忠，或指不履行承诺、义务的人。

Describes a person who is not loyal, especially to a spouse or partner, or who fails to keep a promise or commitment.

1. Not true to duty or obligationB2formal

   Failing to fulfill one's promises, duties, or obligations.

   不忠

   • He was unfaithful to his promise to help.
   • The soldier was punished for being unfaithful to his duty.
   • She felt he had been unfaithful to their agreement.

   同义词disloyalfaithlessfalseperfidiousrecreanttraitoroustreacherousuntrue

   反义词constantdevoteddutifulfaithfulloyalreliablesteadfasttruetrustworthy

2. Sexually disloyalB1formal

   Engaging in a romantic or sexual relationship with someone other than one's partner.

   不忠

   • She discovered her husband had been unfaithful.
   • Being unfaithful often leads to the end of a relationship.
   • He admitted to being unfaithful to his girlfriend.

   同义词adulterouscheatingdisloyalfaithlessstrayingtwo-timinguntrue

   反义词chasteconstantdevotedfaithfulloyaltrue

3. Treacherous or traitorousC1formal

   Having the character of a traitor; betraying trust or allegiance.

   不忠

   • The unfaithful agent sold secrets to the enemy.
   • History remembers him as an unfaithful servant to the crown.
   • Her unfaithful actions endangered the entire mission.

   同义词disloyaldouble-dealingfaithlessfalseperfidiousrenegadetraitoroustreacheroustreasonousuntrue

   反义词devotedfaithfulloyalsteadfasttrue

4. Not trustworthyB2formal

   Lacking reliability or dependability.

   不可靠的

   • An unfaithful friend cannot be relied upon in times of need.
   • The witness was considered unfaithful due to his inconsistent statements.
   • She found his memory unfaithful and full of errors.

   同义词undependableunreliableuntrustworthy

   反义词dependablefaithfulloyalreliabletruetrustworthy